public class Test3 {
    public static void main(String[] args) {
        String str = "abcd";
        for (int i = 0; i < 100; i++) {
            StringBuilder stringBuilder = new StringBuilder();
            stringBuilder.append(str);
            stringBuilder.append(i);
            str = stringBuilder.toString();
        }
        System.out.println(str);
    }
}
